An assessment of array types and processing algorithms for microtremor observations, via the COSMOS Blind Trials

Project: Research

Project Description

In this study, the Consortium of Organizations for Strong Motion Observation Systems (COSMOS) blind trials used microtremor array data from four sites with geology ranging from deep alluvial valleys to an alpine valley. Data were incrementally released to approximately a dozen analysts in four phases: (1) 2-station linear arrays; (2) sparse triangular arrays; (3) complex nested triangular or circular arrays; (4) all available geological control including drill-hole data. While data from one site consisted of recordings from 3-component sensors, the other three sites consisted of data from vertical-component sensors only. The sites covered a range of noise source distributions, ranging from one site with a highly directional microtremor wave field, to others with distributed or omni-directional wave fields.
In this project we review the results based on the different processing algorithms (e.g., beam-forming, spatial autocorrelation, seismic interferometry) as applied by the analysts to the incrementally released data, and then compare the effectiveness between the differing wave-field distributions. The results of the study will aid in building an evidence-based consensus on preferred cost-effective arrays and processing methodology for future site-effect studies.

This project commenced informally in July 2018 when Michael Asten was selected by COSMOS to arrange and analyse a blind trial of different interpretation methodologies for passive seismic observations.

COSMOS in January 2019 agreed to a payment/grant of US$6550 support for my work on this blind trial. It is thus an informal arrangement approved by the COSMOS Board, but not part of any formal Grant scheme. For the purposes of PURE the project started in July 2018 and this project proposal in PURE is both a retrospective project and a continuing project.
Short titlepassive seismic interpretation
StatusFinished
Effective start/end date1/07/1831/12/19

Funding

  • Consortium of Organizations for Strong Motion Observation Systems (COSMOS) : AUD9,225.00